<!DOCTYPE html>
<html>
	<head>
		<meta charset="UTF-8">
		<title>半透明边框</title>
		<style type="text/css">
			body {
				background-color: gray;
			}
			div {
				width: 200px;
				height: 200px;
				background-color: white;
				border: 10px solid rgba(0,0,0,0.1);
				background-clip: padding-box;
			}
		</style>
	</head>
	<body>
		<div id="">
			dd
		</div>
	</body>
</html>
